Juvenogens, biochemically activated juvenoid complexes

The term juvenogen is used to indicate a new class of the complex chemical compounds which generate products with juvenile hormone activity in response to certain biotic or environmental factors. This paper describes mechanism of action of a juvenogen ester prepared by acylation of an active secondary juvenoid alcohol with stearyl chloride. When topically applied, the wax-like ester enters the insect body where it is enzymatically hydrolysed by the carboxylesterase enzymes. The rate of the in vivo enzymatic hydrolysis has been sufficient to liberate biologically active amounts of the juvenoid alcohol product in several species studied. The approximative Km values for the hydrolysis of the ester substrate are in the range of 6.75 × 10−6 to 1.35 × 10−5 M. After treatment with the excessive amounts of the substrate the pupae of Tenebrio liberate 1.66 × 10−3 μmole of the hydrolysis alcohol product per g per day at 27°C. About two orders of magnitude faster hydrolysis of the juvenogen substrate has been found in the larvae of Dysdercus. Here juvenogen has much higher juvenile hormone activity than the hydrolysis alcohol product itself. The juvenogen ester is an environmentally stable, non-volatile, semi-solid wax. It has been suggested that by changing the biologically unimportant acyl component it will be possible to prepare other such complexes with extremely different polarity and volatility. Possible advantages of using juvenogens instead of the regular juvenoids in the field experiments are discussed.